Pls can u advice me what is physical stress? and what causes it?, coz so far i had only heard of mental and chemical stress, thanks

Stress: As you've noted, stress comes in many different forms. Examples of physical stress include various illnesses, especially those that require hospitalization or surgery. Smoking tobacco & drinking alcohol produce physical stress on lungs & heart/liver. Exercise does stress the body to some part but w/appropriate rest, body will get stronger from exercise.